[HttpCache] Store some memcache info to memory dumps for debugging

net/http/mock_http_cache.h

Index: net/http/mock_http_cache.h
diff --git a/net/http/mock_http_cache.h b/net/http/mock_http_cache.h
index f6a805c34f550be39e332c350cc99b20ea6342d3..a24200bf8348cd2ea0ed018a54c7832386195bad 100644
--- a/net/http/mock_http_cache.h
+++ b/net/http/mock_http_cache.h
@@ -134,7 +134,9 @@ class MockDiskCache : public disk_cache::Backend {
   std::unique_ptr<Iterator> CreateIterator() override;
   void GetStats(base::StringPairs* stats) override;
   void OnExternalCacheHit(const std::string& key) override;
-  size_t EstimateMemoryUsage() const override;
+  size_t DumpMemoryStats(
+      base::trace_event::ProcessMemoryDump* pmd,
+      const std::string& parent_absolute_name) const override;
 
   // Returns number of times a cache entry was successfully opened.
   int open_count() const { return open_count_; }